Submergible oil well sealing device with valves and method for installing a submergible oil well sealing device and resuming oil production

ABSTRACT

An oil well sealing device that is submergible for sealing under water oil wells and a method for sealing underwater oil wells in such a fashion that oil production can be resumed are described. The device comprises a housing having at least one lower opening at a lower end of the housing and at least one upper opening at an upper end of the housing; a pump sucking oil through the lower opening into the housing and pushing the oil through the upper opening out of the housing; a connector allowing the lower end of the housing to be fixed to an oil well tube at an oil wellhead; and at least one valve at the lower end of the housing that is closable after the lower end of the housing has been installed to the oil well tube.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-part patent application claiming the benefit of the U.S. non-provisional patent application Ser. No. 12/833,883 filed on Jul. 9, 2010. This prior non-provisional patent application Ser. No. 12/833,883 is herewith incorporated in its entirety by reference.

BACKGROUND OF THE INVENTION

For sealing underwater oil wells, two major problems need to be overcome:

-   -   First, the immense pressure of the oil flow coming out of the         open oil well pushes all elements that are attempted to be         pushed into the oil well for sealing it away. This results         particularly from the high oil pressure in combination with a         relatively large diameter, for instance an oil well tube having         an inner diameter of 20 in.     -   Second, since the oil well is located deep below the water         surface, the oil well is difficult to access due to both the         distance from which any sealing equipment has to be operated, as         well as due to the high water pressure requiring special         equipment. This second part of the sealing problem makes it in         particular difficult to apply the forces needed to counter the         high pressure oil flow to apply a sealing element to the oil         well.

In the prior art, so-called blow-off protectors have been used which are typically battery operated and pinch the entire oil well tube in case of an emergency such that the tube permanently deformed until the entire oil well tube is closed and the oil spill stopped. These blow-off protectors are designed to prevent oil spills in case of an emergency. A major disadvantage of these blow-off protectors is that these destroy the well tube and therefore shut down oil production in the worst case permanently. Particularly if the well is deep under the ocean surface, the oil well is permanently destroyed, or it is at least very costly to restore the oil well tube and resume production and this process takes a significant amount of time. Since good oil wells produce significant value, e.g. 3 Mio US$ daily, it is desirable to resume production, preferably as soon as possible.

It is an object of the invention to create an oil well sealing device that is capable of sealing underwater oil wells in such a fashion that oil production can be restored within a short period of time and at reasonable costs.

SUMMARY OF THE INVENTION

This object is achieved by an oil well sealing device that is submergible for sealing under water oil wells, comprising: a housing having at least one lower opening at a lower end of the housing and at least one upper opening at an upper end of the housing; a pump sucking oil through the lower opening into the housing and pushing the oil through the upper opening out of the housing; a connector allowing the lower end of the housing to be fixed to an oil well tube at an oil wellhead; and at least one valve at the lower end of the housing that is closable after the lower end of the housing has been installed to the oil well tube.

This object is further achieved by a method for installing a submergible oil well sealing device and resuming oil production, comprising: sucking oil from an underwater oil well at a lower end of the oil well sealing device into said device; pushing the sucked-in oil at an upper end of the device through at least one opening out of said device; installing the lower end of the device to the oil well; closing a valve at the lower end of the device; separating a lower end part of a housing of the oil well comprising the valve from the remaining upper part of the oil well sealing device; installing an oil pipe to an upper end of the lower part of the oil well sealing device; and opening the valve for resuming oil production.

DETAILED DESCRIPTION OF THE INVENTION

This apparatus and method according to the invention achieve that the oil well sealing device either lowers the counterforce by actually pumping away the oil at about the same speed as it comes out of the oil well, or even better, depending on the power of the pump, might suck additionally surrounding water into the device. Putting the effect in simple words, the device sucks itself into place and therefore overcomes the need of equipment pushing a sealing device into the well that is very difficult to operate that deep down below the water surface.

According to a preferred embodiment, the sucked in oil and possibly additional water may be guided out of the sealing device in a vertical direction upwards, providing additional thrust pushing the sealing device down into the oil well.

According to a preferred embodiment of the invention, the at least one valve is a mechanical valve that is operated remotely.

According to another preferred embodiment of the invention, the mechanical valve is adapted to be operated by a remotely operated underwater vehicle.

According to another preferred embodiment of the invention, the mechanical valve is connected to an electric motor in a torque transmitting manner and the electric motor is powered by an electric power cable supplying electric power from a location above the water surface.

According to another preferred embodiment of the invention, the oil valve is a hydraulic valve comprising a hydraulic piston and the pressurized hydraulic oil is provided through a hose from above the water surface.

According to another preferred embodiment of the invention, at least two valves are provided at the lower end of the housing; at least one of these two valves is a mechanical valve; and at least another one of these two valves is a hydraulic valve.

According to a preferred embodiment the housing comprises an elongated tube, the lower opening is the entire open cross section of the tube, and the upper opening is a radial opening in the tube. This achieves the maximum intake by avoiding any obstructing of the lower opening of the device. However, as an alternative, also a different shape or partial opening of the lower cross-section is possible, for instance by closing lower opening by a grid. Further, the upper openings do not need to be just radial openings, but could deflect the flow such that it exits the device in the vertical direction upwards, generating additional thrust pushing the entire device in direction of the oil well.

According to another preferred embodiment the pump comprises an auger that rotates within the tubular housing. In the alternative, the pump could actually be of any form or shape. An auger has the advantage of a relatively simple design and can be rotated at relatively high speed, therefore conveying a high oil flow as needed for lowering the pressure from the oil flow enough for pushing the sealing device into the oil well.

According to another preferred embodiment the auger is rotated by a motor that has a reversible rotational direction. Any kind of motor that can be encapsulated in a water tight fashion and therefore operated under water is suitable. Strong electric motors are available both for industrial purposes and for powering automobiles. However, it is also possible to use hydraulic motors that can be fed by hydraulic lines and provide the advantage of high power output at relatively small space. Both electric motors and hydraulic motors can be easily reversed in their rotational direction.

According to another preferred embodiment the lower end of the device is adapted to be connected to a spigot joint that is attachable in a sealed fashion to the oil well. The spigot joint may preferably have a spigot sleeve that can be pre-attached to the tubular housing and protrude therefrom by such a length as it is desired to be inserted into the oil well tube. For sealing the protruding portion in relation to the oil well tube, the protruding portion may carry O-rings on its circumference that engage the inner wall of the oil well tube when inserted therein. Again, O-rings provide the advantage of a self-sealing effected under pressure so that the oil pressure actually helps to accomplish a sealing action.

According to another preferred embodiment the valve is opened and closed by applying torque to the valve by a remotely operated underwater vehicle.

According to another preferred embodiment the valve is opened and closed by applying torque to the valve by an electric motor that is powered by an electric power cable supplying electric power from a location above the water surface.

According to another preferred embodiment the valve is opened and closed by applying hydraulic pressure to a hydraulic piston through a hose from above the water surface.

According to another preferred embodiment opening and closing at least two valves at the lower end of the housing is performed, wherein at least one of these two valves is a mechanical valve and subjected to torque by a remotely operated underwater vehicle; and at least another one of these two valves is a hydraulic valve and subjected to hydraulic pressure through a hose from above the water surface.

According to another preferred embodiment of the method according to the present invention an auger is provided as a pump, said auger rotating within the housing that is shaped as a tube and rotating the auger first into a first direction during installation of the oil well sealing device and then into a second direction after the lower end of the device has been installed to the oil well. An auger is a relatively simple and effective pump and can be rotated at relatively high speed, for instance 2000 to 3000 rpm. However, any other type of pumps can be used such as piston pumps or rotary vane pumps.

According to another preferred embodiment of the method according to the present invention a hollow spigot sleeve is installed to the lower end of the device and then the spigot sleeve is pushed in a sealing fashion into the oil well. However, it is also possible to reverse the sequence of installation steps according to another preferred embodiment, namely by installing a hollow spigot sleeve to the oil well and then installing the lower end of the device to the spigot sleeve. The latter installation sequence might be a little more cumbersome since it requires the extra step of attaching the spigot sleeve first to the oil well tube, but should also be possible since the spigot sleeve is hollow and therefore free from being subjected to a high force rejecting the spigot sleeve by the oil flow from the oil well.

The invention is described in more detail in the following by referring to the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic side sectional view of an embodiment of the oil well sealing device according to the present invention as described in the parent U.S. non-provisional application Ser. No. 12/833,883.

FIG. 2 shows a schematic side sectional view of a second embodiment comprising a hydraulic valve and a mechanical valve at a lower part of the oil well sealing device.

DETAILED DESCRIPTION OF THE DRAWINGS

The FIG. 1 shows a schematic side view of the submerged oil well sealing device 1 for sealing underwater oil wells. The device comprises an upper end 2 and a lower end 3 and extends during use substantially in vertical direction. The device comprises the shape of an elongated tube, particularly sized for having a diameter of a typical oil well tube 5, for instance a diameter of 20 in or larger, depending on the size of the oil well. The entire device is for instance 18 ft. long. A spigot sleeve 6 is either pre-installed into the housing 4, for instance by a press fitting or welded to the housing 4, or it is pre-installed into the oil well tube 5 so that the spigot sleeve protrudes the oil well tube 5 by a certain distance. This protruding part has an outer diameter that is a little smaller than the inner diameter of the tube-shaped housing 4. In any of the two aforementioned alternatives, the spigot sleeve is designed to center the housing 4 and connect it with of the oil well tube 5. O-rings 19 can optionally be provided, sealing the spigot sleeve 6 with respect to the oil well tube 5, or optionally also with respect to the tube-shaped housing 4.

The oil well sealing device 1 comprises further a closing element 7 that is shaped according to this embodiment as a cylinder, comprises several upper openings 8, in this case eight upper openings 8 spaced apart around the circumference of the tube-shaped housing 4 at the upper end 2 of the device, and a lower opening 9 that is simply according to this embodiment the lower open cross-section of the tube-shaped housing.

An auger 10 is provided within the tube-shaped housing 4, and is driven via a shaft 11 that is rotated by an electric motor 12. Two hydraulic cylinders 13 are provided for moving the closing element 7 along the tube-shaped housing 4, particularly into a closing position where the upper openings 8 are closed, i.e. substantially to prevent that oil coming from the oil well can escape the sealing device once it has been installed and is moved into its closed position. The closing element 7 also prevents water from the outside to penetrate through the upper openings 8 into the sealing device. When the closing element 7 has been moved into its closing position, one or more biased locking pins 14 may snap into place, locking the closing element into its closing position. These locking pins 14 may for instance snap into holes or recesses 15 that are formed in the wall of the tube-shaped housing 4.

The closing element 7 may carry two sets of O-rings, namely a first set of O-rings 16 and a second set of O-rings 17. These two sets of O-rings 16 and 17 are spaced apart by a distance that is larger than the longitudinal size of the openings 8 measured in the longitudinal direction of the tube-shaped housing 4. In the locked position of the closing element 7, the first set of O-rings 16 is vertically above the upper openings 8, and the second set of O-rings 17 is in vertical direction in the locked position of the closing element 7 below the upper openings 8.

In the following, the process of installing the oil well sealing device and finally sealing the oil well are described.

The oil well sealing device is used as a stand-by device in case an underwater oil well gets out of control as far as the ability to seal the oil well is concerned. The main problem of sealing an oil well is the extreme pressure under which oil comes out of the oil well, creating a fast flow of pressurized oil. This powerful oil flow prevents installing any plugs sealing the well. The embodiment of the invention as described above targets this problem by actively pumping the oil off so that the pressure pushing any sealing plug into the oil well is reduced to a minimum that can be overcome by force or gravity, or in the ideal situation, even provides a positive attractive force sucking the entire oil well sealing device into place.

The device 1 is lowered to be basically aligned with the oil well at such a distance that the oil flow coming out of the oil well tube 5 allows without any further action. Then, the electric motor 12 is started. As an electric motor, for instance a motor of an electric car can be used that is capable of providing rotational speeds of over 2000 rpm. Via a shaft 11, the auger 10 is rotated, sucking in water and some oil through a lower opening 9. If the spigot sleeve 6 is pre-attached to the tube-shaped housing 4, the mixture of water and oil is sucked in through the lower opening 18 of the spigot sleeve 6. The mixture of oil and water sucked into the tube-shaped housing by the auger can leave the housing 4 radially through the upper openings 8. In another preferred embodiment, outlet tubes can be attached to the radial openings 8, deflecting the radial liquid stream upwards in axial direction of the tube-shaped housing, creating additional push in the direction of the oil well. Instead of radial upper openings, it is also possible to guide the flow through the tube-shaped housing 4 to the very upper end and exhaust this flow in a vertical direction upwards, creating extra thrust and therefore push on the entire device 1 downwards. In this case, the electric motor 12 needs to be either installed laterally, or tubes can guide the flow around the electric motor 12.

The sucking action allows lowering the entire device 1 even further, until the pre-attached spigot sleeve 6 can enter into the oil well tube 5. The tube-shaped housing 4 can then be anchored to the oil well tube 5 in a conventional manner, for instance by anchors or other fastening devices. Also, the spigot sleeve 6 may be pressed-fit into the oil well 5. Also, locking pins or locking screws are an option.

After the tube-shaped housing 4 has been fixed to the oil well tube 5, the auger still rotates initially in the same direction, now only pumping oil and no water from the oil well out through the upper openings 8. Since the ultimate goal is to seal the oil well, now the upper openings 8 need to be closed. For this purpose, the closing element 7 is pushed down via the hydraulic cylinders 13 so that the second set of O-rings 17 rests below the openings 6 while the first set of O-rings still remains above the openings 8. In other words, the openings 8 are sandwiched between the two sets of O-rings 16 and 17 in the closing position of the closing element 7. When the closing element 7 has reached its closing position, it can be locked with respect to the tube-shaped housing 4, for instance by locking pins 14 snapping into respective recesses or holes 15 provided in the wall of the tube-shaped housing 4. The closing element 7 may likewise be locked by other means into its closing position, for instance by locking pins inserted from the outside of the housing 4, or any other type of latch that may for instance engage the plane top face of the cylinder-shaped closing element 7.

In order to facilitate the movement of the closing element 7 into its closing position, the rotational direction of the auger can be reversed prior to or during movement of the closing element. This reverses the pumping direction, namely now with the reversed rotational direction no oil is pumped out of the oil well, but to the contrary, water is pumped from the openings 8 into the oil well if the pumping pressure and respectively the electric motor 12 are strong enough for reversing entirely the direction of flow. However, even if the power of the electric motor 12 and respectively the rotational speed of the auger are not sufficient for entirely reversing the direction of flow, at least the pressure from the oil acting upon the lower front face of the closing element is reduced, allowing the closing element 7 to be pushed downwards with less force by the hydraulic cylinders 13.

With the closing element 7 locked in its closing position and the tube-shaped housing 4 being attached to the oil well tube 5, the oil well is now sealed and the electric motor 12 can be turned off.

Another embodiment is shown in FIG. 2. The same reference numerals that are in common with FIG. 1 are also used in the embodiment shown in FIG. 2. This embodiment shown in FIG. 2 distinguishes from the embodiment shown in FIG. 1 by comprising at the lower end of the device a first hydraulic valve 20 and a second mechanical valve 21. Even though it is possible to provide only one of the valves 20 and 21, the redundancy in providing two valves that are preferably operated by different mechanisms enhances the safety against failure of one of the valves.

At the very lower end, the device 1 is basically connected to the oil well tube 5 as described in FIG. 1 with the additional feature of providing a flange 37 at the lower end of the housing of the device that can be connected to a corresponding flange of the oil well tube 5. In contrast to the embodiments shown in FIG. 1, the closing element 7 (FIG. 1) is omitted, but instead the lower valves 20 and 21 have the function of shutting the oil flow down after the oil well sealing device 1 has been fixed to the oil well tube 5. The entire oil well sealing device 1 can be separated into an upper device part 22 comprising the housing 4 and the electric motor 12 and a lower device part 23 for separating the lower and upper device parts 22, 23 from each other. For instance as a separable connection, a connection via a flange 24 is possible. Any type of standard, fluid tight connection between the upper and the lower housing parts 22, 23 would work for this purpose.

After having installed the oil well sealing device 1 to the oil well tube 5, either the first hydraulic valve 20, or the second mechanical valve 21 can be closed, or both valves 20 and 21 can be closed. Preferably, it is first tried to close the hydraulic valve 20. For this purpose, pressurized hydraulic fluid can be guided through a conduct 25 into a piston chamber 26, pressurizing a piston 27 that is moved from its first position shown in interrupted lines into a second position shown in solid lines. While maintaining the hydraulic pressure in the piston chamber 26, the upper device part 22 can be removed, for instance by unscrewing screws 28 that flange the upper part device part 22 to the lower device part 23. Instead of maintaining the pressure in the piston chamber 26, it is also possible to lock the piston 27 mechanically in place so that it maintains its closing position shown in solid lines even if the pressure in the piston chamber 26 is released.

After the upper oil well sealing device part 22 has been removed and the hydraulic valve 20 maintains its closing position, the upper device part 22 can be substituted by an oil pipeline. After the oil pipeline has been fixed in a fluid tight manner to the lower oil well sealing device part 23, is possible to release the piston, for instance by pressurizing a piston chamber 29 on the opposite side of the piston 27. After the piston has been moved back into its open position shown in interrupted lines, oil production is restored.

The hydraulic valve 20 has the advantage that hydraulic oil can be easily supplied from a location above the water surface so that no operation by external remotely controlled devices is necessary. Also, the hydraulic mechanism is relatively simple and therefore reliable. However, if this hydraulic valve 20 turns out to fail due to unforeseen circumstances, it is preferable to provide redundancy by the second, mechanical valve that is operated by rotating a spindle 31 moving a valve slider 32 from an open position shown in interrupted lines into a closed position shown in solid lines. This spindle 31 can be rotated by coupling any kind of torque transmitting element to it, for instance like in this embodiment coupling it a claw 33 rotated by an external remotely controlled underwater vehicle, for instance by coupling the claw 33 to a hexagon 34 that is connected in a torque transmitting manner to the spindle 31 or integrally formed therewith. In the alternative, the spindle 31 can be rotated by an electric motor 35 receiving power through power lines 36 that can be guided all the way to a location above the water surface. The electric motor can be connected to the lower part 23 in the oil well sealing device 1.

Again, the upper part 22 of the oil well sealing device 1 can be separated from the lower part 23 and substituted by an oil pipeline, and after the substitution the mechanical valve 21 can be opened again by rotating the spindle 31 into the opposite direction than the closing direction. This can again be accomplished by either the electric motor 35, for instance changing poles to reverse the rotational direction, or by the remotely controlled underwater vehicle. It is to be understood that the substitution of the upper part 22 of the oil well sealing device 1 can be accomplished after the hydraulic valve 20, or the mechanical valve 21, or both valves have been closed, and respectively oil production is restored after all valves that have been previously closed are opened again after installation of the oil pipeline. 

1. An oil well sealing device that is submergible for sealing under water oil wells, comprising: a housing having at least one lower opening at a lower end of the housing and at least one upper opening at an upper end of the housing; a pump sucking oil through the lower opening into the housing and pushing the oil through the upper opening out of the housing; a connector allowing the lower end of the housing to be fixed to an oil well tube at an oil wellhead; and at least one valve at the lower end of the housing that is closable after the lower end of the housing has been installed to the oil well tube.
 2. The oil well sealing device according to claim 1, wherein the at least one valve is a mechanical valve that is operated remotely.
 3. The oil well sealing device according to claim 2, wherein the mechanical valve is adapted to be operated by a remotely operated underwater vehicle.
 4. The oil well sealing device according to claim 2, wherein the mechanical valve is connected to an electric motor in a torque transmitting manner and the electric motor is powered by an electric power cable leading to a location above the water surface.
 5. The oil well sealing device according to claim 1, wherein the oil valve is a hydraulic valve comprising a hydraulic piston that is connected to a hydraulic pressure fluid conduct leading to a location above the water surface.
 6. The oil well sealing device according to claim 1, wherein at least two valves are provided at the lower end of the housing; at least one of these two valves is a mechanical valve; and at least another one of these two valves is a hydraulic valve.
 7. The oil well sealing device according to claim 1, wherein the housing comprises an elongated tube, the lower opening is the entire open cross section of the tube, and the upper opening is a radial opening in the tube.
 8. The oil well sealing device according to claim 7, wherein the pump comprises an auger that rotates within the tubular housing.
 9. The oil well sealing device according to claim 8, wherein the auger is rotated by a motor that has a reversible rotational direction.
 10. The oil well sealing device according to claim 1, wherein the lower end of the device is adapted to be connected to a spigot joint that is attachable in a sealed fashion to the oil well.
 11. A method for installing a submergible oil well sealing device and resuming oil production, comprising: sucking oil from an underwater oil well at a lower end of the oil well sealing device into said device; pushing the sucked-in oil at an upper end of the device through at least one opening out of said device; installing the lower end of the device to the oil well; closing a valve at the lower end of the device; separating a lower end part of a housing of the oil well comprising the valve from the remaining upper part of the oil well sealing device; installing an oil pipe to an upper end of the lower part of the oil well sealing device; and opening the valve for resuming oil production.
 12. The method according to claim 11, comprising opening and closing the valve by applying torque to the valve by a remotely operated underwater vehicle.
 13. The method according to claim 12, comprising opening and closing the valve by applying torque to the valve by an electric motor that is powered by an electric power cable supplying electric power from a location above the water surface.
 14. The method according to claim 11, comprising opening and closing the valve by applying hydraulic pressure to a hydraulic piston through a hose from above the water surface.
 15. The method according to claim 11, comprising opening and closing at least two valves at the lower end of the housing, wherein at least one of these two valves is a mechanical valve and subjected to torque by a remotely operated underwater vehicle; and at least another one of these two valves is a hydraulic valve and subjected to hydraulic pressure through a hose from above the water surface. 